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<base href="https://bugs.freedesktop.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Monitor on 2nd DisplayPort is not initialized"
href="https://bugs.freedesktop.org/show_bug.cgi?id=107446">107446</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Monitor on 2nd DisplayPort is not initialized
</td>
</tr>
<tr>
<th>Product</th>
<td>DRI
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>Other
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>medium
</td>
</tr>
<tr>
<th>Component</th>
<td>DRM/Intel
</td>
</tr>
<tr>
<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>glogow@fbihome.de
</td>
</tr>
<tr>
<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>CC</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr></table>
<p>
<div>
<pre>I'm on Ubuntu 18.04.
While analyzing <a class="bz_bug_link
bz_status_NEW "
title="NEW - Black or broken VT when loading i915.ko "late""
href="show_bug.cgi?id=107441">bug 107441</a> I found that kernels since 4.17 failed to initialize
the 2nd monitor attached to my Skylake HW, an Acer n4640g (Celeron® G3900T").
The most obvious missing lines from the DRM debug diff is the missing
retraining like:
[drm:intel_dp_check_link_status [i915]] DDI D: channel EQ not ok, retraining
...
and then there is the missing drm_atomic_add_affected_connectors:
[drm:intel_dump_pipe_config [i915]] planes on this crtc
[drm:intel_dump_pipe_config [i915]] [PLANE:28:plane 1A] disabled, scaler_id =
-1
-[drm:intel_dump_pipe_config [i915]] [PLANE:31:plane 2A] disabled, scaler_id =
-1
-[drm:intel_dump_pipe_config [i915]] [PLANE:34:cursor A] disabled, scaler_id =
-1
-[drm:drm_atomic_add_affected_connectors [drm]] Adding all current connectors
for [CRTC:47:pipe B] to (ptrval)
-[drm:intel_atomic_check [i915]] [CONNECTOR:61:DP-3] checking for sink bpp
constrains
+[drm:intel_dump_pipe_config [i915]] [PLANE:33:plane 2A] disabled, scaler_id =
-1
+[drm:intel_dump_pipe_config [i915]] [PLANE:38:cursor A] disabled, scaler_id =
-1
+[drm:intel_atomic_check [i915]] [CONNECTOR:72:DP-3] checking for sink bpp
constrains
[drm:intel_atomic_check [i915]] clamping display bpp (was 36) to EDID reported
max of 24
[drm:intel_dp_compute_config [i915]] DP link computation with max lane count 4
max bw 270000 pixel clock 148500KHz
No idea if it's related, but 4.17 is also the first kernel to spill some ACPI
error messages before the splash screen:
[ 0.049039] ACPI Error: Result stack is empty! State= (ptrval)
(20180313/dswstate-65)
[ 0.049046] ACPI Error: AE_AML_NO_RETURN_VALUE, Missing or null operand
(20180313/dsutils-612)
[ 0.049050] ACPI Error: AE_AML_NO_RETURN_VALUE, While creating Arg 0
(20180313/dsutils-727)
Tested kernels are:
* Ok - Ubuntu 18.04 + linux-image-4.15.0-29-generic (4.15.0-29.31)
* Ok - Ubuntu 18.04 + linux-image-4.16.18-041618-generic
(4.16.18-041618.201806252030)
* Fail - Ubuntu 18.04 + linux-image-4.17.11-041711-generic
(4.17.11-041711.201807280505)
* Fail - Ubuntu 18.04 + linux-image-4.18.0-041800rc7-generic
(4.18.0-041800rc7.201807292230)</pre>
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